Electric control device



Jan. 17, 1933. c w KUHN 1,894,404

ELECTRIC CONTROL DEVICE Original Filed June 24, 1929 IN VEN TOR.

A TTORNEY Patented Jan. 17, 1933 UNITED STATES 11.5mm OFFICE CLARENCE W.-KUHN, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO CUTLER-HAMMER, INC-,0]? MILWAUKEE, WISCONSIN, A CORPORATION OF DELAWARE ELECTRIC CONTROL DEVICE Application filed June 24, 1929, Serial This invention relates to electric control devices, and while not limited thereto is particularly applicable to devices for controlling electric motors.

The invention has among its objects to provide an improved unitary control device which provides for starting and stoppingof an electric motor, and which also provides for overload protection thereof.

Another object is to provide a simple,

rugged and compact device of the aforesaid character including separate start and stop push buttons and a cutout device which is to be tripped under overload conditions and is adapted to be reset by the stop push button. Another object is to provide a device of the aforesaid character employing an electrothermal cutout device of the self-soldering yp Various other objects and advantages of the invention will hereinafter appear.

The accompanyingdrawing illustrates an embodiment of the invention which will now be described, it being understood that the embodiment illustrated. is sus'ceptibleof modification without departing from the spirit and scope of the appended claims.

In the drawing Figure 1 is a front elevational view of a control device embodying the invention;

Fig. 2 is a rear elevational view thereof;

Figs. 3 and 4 are sectional views taken on lines 3-3 and 4-4, respectively, of Fig. 1;

Figs. 5. 6 and 7 are detail views partly in section of certain .of the parts shown in Figs. 3 and 4, and

Fig. 8 is a diagrammatic view illustrating the circuit connections for the device.

Referring to the drawing, the control device shown therein as an embodiment of the invention comprises an electro-thermal cutout device 1, a start push button switch 2 and a stop push button switch 3. These parts are carried by an insulating base 4. and as hereinafter set forth the same are adapted to control the line switch of an electric motor to start and stop the motor and to also provide overload protection thereof.

Cutout device 1 includes a-pair of L-shaped contacts 5 and 6 fixed to the rear face of base No. 373,172. Renewed April 11, 1932.

4and arranged in opposed relation, and a pair of cooperating contact elements 7- and 8, each of which is associated with an electro-thermal device 9.

Each of the electro-thermal devices 9 includes an electric heater 10, a cup member 11 and a ratchet pin 12 located within said cup member and connected thereto by a soldered connection 13. As shown in Fig. 3 the heaters 10 are of helical form and are arranged within recesses 14 in the front face of base 4. Each of the heaters is surrounded by a heat insulating bushing 15 and the terminals of one of the heaters are connected to binding posts 16-46 mounted on one end of base 4 while the terminals of the other heater are connected to binding posts 17 17 mounted on the opposite end of said base. The cup members 11 are fixed within openings in base 4 with their open ends flush with the rear face of said base and each projects into its associated heater 10. As shown in Fig. 7, each of the cup members 11. is provided with a small end opening 18 and a small side opening 18 to facilitate introduction ofthe solder required for-connection 13 and each contains a ball 19 for closing the end opening 18 to prevent escape of the solder upon melting thereof. Also as shown in Fig. 7 each of the ratchet pins 12 has an enlarged corrugated cylindrical head 20 which projects beyond its associated cup member and is provided with a cylindrical projection 21 of reduced diameter.

Contact elements 7 and 8 are provided with similarly shaped insulating-blocks 22 and 23, respectively, each of which carries a spring contact 24. As shown in Figs. 2 and 3 said blocks are arranged in opposed relation and each is pivotally mounted upon the cylintate said blocks in opposite directions. Each of the blocks 22 and 23 is recessed to receive the head 20 of its associated ratchet pin 12 v contact element 7 permits clockwise rotation ofblock 22 on its associated ratchet pin 12 and prevents counterclockwise rotation thereon, The pawl 28 of contact element 8 acts in a similar manner, but is arranged to permit counterclockwise rotation of block 23 on its associated ratchet pin 12 and to prevent clockwise rotation thereon. 1

From the foregoing it is apparent that under normal conditions the solder connections 13 of the thermal devices 9 are solid and prevent rotation of the associated ratchet pins 12. Thus under normal conditions said thermal devices are adapted to act through the medium of the pawls 28 to hold the contact elements 7 and 8 in positions wherein the spring contacts 24 engage the stationary contacts 5 and 6 to establish a circuit between the latter. Under given overload conditions the heaters 10 serve to fuse one-or both of the solder connections 13' of the thermal.

devices 9 and upon fusion of either of said connections the associated ratchet pin is released to permit its associated contact element to move to open position under the action of spring-26. Resetting of the contact elements 7 and 8 is effected by a reciprocable cone element 29 which is located with n an opening in base 4, and is associated with the stop push button'3 as hereinafter set forth. Said cone element is movable downwardly from the position shown in Fig. 4 and during such movement the same is adapted to engage the insulating blocks 22 and 23 to move the contact elements 7. and 8 into closed f position.

. The start push button switch 2 is provided with a pair of stationary contacts 30 and 31 and a cooperating bridging contact 32' while the stop push button switch 3 is provided with a pair of stationary contacts 33'and 34 and a cooperating bridging contact 35. The stationary contacts of said push buttons are mounted upon a rectangular insulating plate 36 which is held in spaced relation wlth re spect to the front face of base 4 by insulating bushings 37, one of which is located at each corner of said plate. Said plate is fixed to base 4 by screws 38 to 41, inclusive, each of which passes through base 4 and one of the bushings 37. The screws 38- and 39 pass through the stationary contacts 5 and 6, respectively, to fix said contacts to base 4. and the former screw also passes through contact 33 tofix the latter to the front fact of plate 36and to electrically connect the same to contact:5. The contacts 30 and 31 are fixed to thej jf -in-t face of plate 36 by the screws 40 ant-1:41 while contact 34 is fixed insulating to the front face of said plate by a screw 42 and is connected to contact 31 by a plate 43.

The bridging contact 32 of the start push button switch is arranged above its associated stationary contacts and is fixed to a reciprocable pin 45 having a push button 46 on the outer end thereof. Said pin has an enlarged head 47 on the inner end thereof which. is slidable within an opening in base 4 and the same is supported at its outer end within an insulating bushing 48 which abuts contact 32 and is slidable within an opening in plate 36. Pin 45 is biased to hold contact 32 in the position shown in Fig. 3 by a spring 49 which surrounds said pin and is held under compression between an insulating washer 50 which rests on the front face of base 4 and an insulating washer 51 which rests on the rear face of plate 36 and abuts the inner end of I bushing 48.

As shown in Fig. 5 the stationary contacts 33 and 34 of the stop push button switch 3 b 1 Cbntact 35 is mounted upon a reciprocab'le pin 53 having apush button 54 fixed to its outer end' and. havlng its inner end fixed to the cone element 29. As shown in Fig. 4

contact 35 is biased towards its associated stationary contacts by a spring 55 which surrounds the pin 53 and is held under compression between an insulating washer 56 which rests on the'under face of contact 35 and an insulating washer 57 which seats within a counterbore in the front face of base 4. Also as shown in Fig. 4 contact 35 is insulated from-pin 53 by a bushing 58 and a second bushing 59 which surrounds bushing 58 serves to center the pin 53 within an opening in plate 36 and also acts as an abutment for contact 35. Upon depression of push button 54 the contact 35 is first moved out of engagement with contacts 33 and 34 and thereafter the cone element is moved between insulating blocks 22 and 23 to efi'ect resettin of contact elements 7 and 8.

The a contactor of an alternating current electric motor M to start and stop the motor and to provide overload protection thereof. As shown in this figure the motor is adapted to be connected to a three phase supply circuit.

ove described control device maybe used as shown in Fig. 8 tocontrol the line 11;

/ the motor at any time by depression of L and L Contactor 60 is provided with auxiliary contacts 60 and in closing the same maintains itself by a circuit extending from line L through said auxiliary contacts 60" through the stop push button .switch 3, through the cutout device 1 and thence through the operating coil 60 to line L". Under given overloadponditions one or both of the contact elements 7 and 8 are released under the action of the heaters 10 and the aforedescribe'd maintaining circuit for coil 60 is interrupted to effect opening of the line contactor 60. The maintaining circuit of coil 60 can also be interrupted to stop stop push button switch 3. Upon opening of either of the contact elements 7 or 8 of cutout device 1 the same can be reset by depression of stop push button 3 as hereinbefore' described.

What I claim as new and desire to secure by Letters Patent is:

1. The combination with a manually op.--

erated switch for effecting interruption of the supply circuit of an electric translating device, of an electro-thermally responsive cutout device operable independently of said switch to interrupt the supply circuit of the translating device under given overload conditions, and means associated with said manually operated switch for eflecting resetting.

of said cutout device.

'2. A unitary control device for electric translating apparatus including a manually controlled stop switch, an electro-thermally responsive circuit breaking device operable associated with said stop switch for effecting resetting ofsaid circuit breaking device upon response thereof.

3. A unitary control device for electric translating apparatus including a control switch biased towards closed position, a cutout device connected in series with said control switch and biased towards open position, electro-thermal' means adapted to normally maintain said cutout device in closed position and responsive-to .release the same to permit opening thereof, and common operating means for opening said control switch indpendently of said stop switch, and means and for resetting said cutout device in closed ually operable control switch mounted upon position.

4. A unitary control device for electric translating apparatus, including a cutout de 5. A control unit for electric translating devices, comprising an insulating base, a cutout device carried by said base and having electro-thermal means associated therewith nected in series with said cutout device, said latter push buttonhaving means amociated therewith for effecting resetting of said cutout device.

6. A control unit for electric translating devices, comprising an insulating base, a cutout device carried by said base and including a pair of series connected switch elements biased towards open position, an electrothermally responsive element associated with each of said switch elements for maintaining the same in closed position subject to release under given current conditions in the supply circuit of the translating device, and a normally open starting push button switch and a normally closed stop push button switch carried by said base and connected in series with the switch elements of said cutout device, said latter push button switch having means associated therewith which is adapted to act upon opening movement to effect resetting of both of said switch elements in closed position.

7. A control unit for electric translating devices comprising an insulating base, a manlating device, and means associated with said control switch and adapted to act upon opening thereof to effect setting of said cut-out device in' closed position.

8. A control unit for electric translating devices comprising an insulating base, a manone side of said base and biased towards closed position, a cut-out device mounted upon the opposite side of said base and including a pair of switches connected in series with said control switch, and each including a movable switch element biased towards open position, an electro-thermal element associated with each of said switch elements for maintaining the same in closed position subject to release under given current conditions in the supply circuit of the translating device, and means associated with said control switch and adapted to actupon opening thereof to efi'ect setting of the movable switch elements of said cut-out device in closed position.

" 9. In a control unit for electric translating devices, the combination with a normally closed manually operable stop switch, of an electro-thermal circuit breaker including a plurality of switch elements connected in series with said stop switch, and means associated with said stop switch and adapted to act upon opening thereof to effect setting of said switch elements in closedposition.

10. In a control unit for electric translating devices, the combination with a cut-out device biased towards open position, of a normally closed manually operable stop switch connected in series with said cut-out device and adapted when moved to open position to effect closure of said cut-out device, and means for holding said cut-out device in closed position subject to release under given current conditions in the supply circuit of the translating device, said means including a fusibly mounted restraining element and an electric heater located adjacent said element and ada ted to be connected in the supply circuit 0 the translating device.

11. In a control unit for electric translating devices, the combination with an insulating base, of a cut-out device mounted upon one side of said base and including a pair of switch members each of which is biased to wards open position, a manually operable stop switch mounted upon the opposite side of said base and connected in series with said cut-out device, said stop switch when opened being adapted to effect closure of the switch members of said cut-out device, and means for maintaining said cut-out device in closed position subject to release under given current conditions in the supply circuit of the translating device, said means including a fusibly mounted restraining element associated with each of said switch members, and an electric heater associated with each of said restraining elements and adapted to be co'n nected in the supply circuit of the translating device.-

12. In combination, a translating circuit, a switch controlling the continuity of said circuit, power means for moving said switch from one position to another, an electrothermal device responsive to given electrical conditions in said circuit to effect opening of said switch, and a manual element operable to efiect opening. of said switch at will and. resetting of said electro-thermal device following response of the latter, said manual element when operated to reset said device re-- quiring a return movement incident to reclosure of said switch and and being sub: jected to a bias for effecting such return movement.

13. In combination, a translating circuit, a switch controlling the continuity of said circuit, power means for moving said swltch from one position to another, an electrothermal device responsive to g1ven electrical conditions in said clrcuit to effect opening of said switch and a manual element operable in a given manner to eflect opening of sai switch at will and in a like manner to reset said electro-thermal device following response thereof, said manual element when so operated requirin a return movement incident to reclosure of said switch.

14. In combination, a translating circuit, a switch controlling the continuity of said circuit, control means for said switch comprising power means, an electro-thermal device and a manual element, said power means affording an operating means for said switch whereby said switchmay be operated and released for making and breaking circuit repeatedly while said electro-thermal device a given setting, said electro-thermal devlce being responsive under given electrical con-.

ditions in said circuit to' cause said switch to open and to remain open until said device is reset, said manual element affording means for effecting opening-of said switch at will while said electro-thermal device remains set and for resetting said electro-thermal device following response of the latter.

15. In combination, a a switch controlling the continuity of said circuit and control means for said switch comprising power means, an electro-thermal device and a manual element, said control means providing for power operation of said switch and release thereof for making and breaking circuit repeatedly while said electro-thermal device has a given setting, said electro-thermal device being'responsive under given electrical conditions in said circuit to cause sa d switch to open and to remain open until said device is reset, said manual element being operable following response of said electrothermal device to reset the latter and said translating circuit,

manual element when so operated requirlng hereunto sub- 

